// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_REGLIST_H_
#define V8_REGLIST_H_

#include <cstdint>

#include "src/base/bits.h"
#include "src/base/template-utils.h"

namespace v8 {
namespace internal {

// Register configurations.
#if V8_TARGET_ARCH_ARM64
    typedef uint64_t RegList;
#else
    typedef uint32_t RegList;
#endif

    // Get the number of registers in a given register list.
    constexpr int NumRegs(RegList list)
    {
        return base::bits::CountPopulation(list);
    }

    // Combine two RegLists by building the union of the contained registers.
    // Implemented as a Functor to pass it to base::fold even on gcc < 5 (see
    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52892).
    // TODO(clemensh): Remove this once we require gcc >= 5.0.
    struct CombineRegListsFunctor {
        constexpr RegList operator()(RegList list1, RegList list2) const
        {
            return list1 | list2;
        }
    };

    // Combine several RegLists by building the union of the contained registers.
    template <typename... RegLists>
    constexpr RegList CombineRegLists(RegLists... lists)
    {
        return base::fold(CombineRegListsFunctor {}, 0, lists...);
    }

} // namespace internal
} // namespace v8

#endif // V8_REGLIST_H_
